Process and apparatus for treating conductors



May 30, 1933. A. o. AUSTIN 1,912,170

PROCESS AND APPARATUS FOR TREATING CONDUCTORS Filed Aug. 30, 1930 INVENTOR A TTORNE Y Patented May 30, 1933 oFFicEI ARTHUR 0. Aus ria, on NEAR :enniasa ron, onio risocnss AND. er'rannrns non TREATING joonnncrons Application filed August so; 1930 eam. 479,010.

' This invention relates to a process for restricting corona losses from high voltage conductor lines and to apparatus for treating the line.

The invention has for one of its objects the provision of a process and apparatus which will render a conductor line less liable to corona losses, and by which the line maybe quickly and economically treated although it may be located in a position where it is not easily accessible. V I

Other objects and advantages will appear from the following description.

The invention is exemplified by thecombination and arrangement of parts-shown n the accompanying drawingand described in the following specification and by the process explainedin the specification. The invention is more particularly pointed out in the appended claims.

In the drawing: Fig. 1 is anelevation' of one form of apparatus for treating a conductor line according to the present invention. v

Fig. 2 is a sectionon line 22of Fig. 1. Fig. 3 is a sectionon line 3-1-3 of Fig. 1. 'Inthe transmission of'power'at high voltages, it is essential that the corona losses be 'maintained within economical limits. Any expedient which will permit of a higher op-,

erating'voltage without producing prohibitive corona losses or excessive radio interference, due to discharges irom the conductor,

is of considerable" economical importance in many transmission lines. i

In transmission lines where the amount of energy transmitted i's'not sufficient to warrant a large diameter of conductor but where it is desirable tonsea high voltage because of interconnection with other lines or to provide for future loads which would require a high voltage, it may be very desirable tou se 'a small conductor. With thepr esentinvention, it is possible to use a small 'conductor and avoid some ofthe difficulties which have heretofore beenencou iitered in transmission worln On some systems, it is advisable to raise the corona point or to reduce radio interference in restricted localities only, in which case the improved method of treating the conductor may be warranted even though notapplied to a transmission line as a whole. 'In my prior Patent #1,62'6,777 an 'improved type of conductor is shown for reducing discharge from high voltage oondnctors.

With this type of conductor, it has sometimes been-difli-cult to obtain an insulat ing coating which will have the desired length of life, although an improvement in the coating may at any time greatly improve this construction. In order to take advantage of the insulated strand ofthe conductor covered with a dielectric medium, shown in my prior patent, a method of coating the guard or control strands is provided? by the present 6 invention which is easily and" cheaply; applied. By using this method with conductors having guard strands, it' is possible to apply air-insulating covering very easily by a traveling, mechanism placed onv the conductor. As the guard strands constitute but a small portion of the surface, is possible to coat these without" applying a large amount of material which might otherwise be required, due to the capillary attraction of the V strands.

The method, however, is applicable for improving the ordinary rope lay or smooth lay conductors used in transmission lines where itis-desirable to reduce the discharge from V theconductors. The method applies more particnlarly, however, to the special type of conductors having projecting guard *strands as disclosedin my prior patent. 4

One methodof treating the conductor ac 8 cording to the present invention involves the use of a small paint or enamelling carriage which may bedrawn along the conductor by any suitable means. The nature of theeqnipment used for applying the coating will, .of

'necessity,depend upon the style of'conductor; The coating may be appliedby flowing the material over the conductor with a suit 'able wiping means to take off excess material 7,

or by a suitable air brush-or a rollerfcarrying the coating'material which is taken from a suitable supply. If desired, the paint or enamelling carriage may be operated byhand with an operator seated with the mechanism; the carriagebeing so arrangedthat' the conditions and the result d of heat during the curing or .dryingprocess This heat may be readily supplied in a trans mission line by using sufiicient current. in the conductor for curing purposes. By coating the conductor with enamel of increased dielectric strength, is possible to reduce the losses due to roughness on the conductor either produced in drawing or by deposits or by damage during installation.

It is readily seen that where conductors are used with the extending control or guard strands, the amount of coating material required may be very small as compared to the coating. of an ordinary conductor. The weight of the conductor ill also be less than the regular.conductor coatcdas'in the latter case anappreciable amount of material is likely to be drawn into the conductor through capillary attractlon. It is possible, however, to use a very thick enamel for coating which may be applied by a series of flexible rollers. hiIe these rollers are spaced somedistance apart, it is possible that several light coatings may be applied in rapidsuccession without using a large quantity of material, which is of little use.

WVhere tower clearances aresufiicient, it is possible to arrange a carriage so that an operat0r may coattheconductor without interruption of service. If the means used to-propel or'draw' the coating carriage is insulated from ground, t is also posslble to'treatthe conductorsduring the normal operation of the transmission system. The means adopted for coating will, of necessity, depend upon sired; v Where the'current, flowing in the conductor is of appreciable magnitude, it is'possible to use the magnetic field set up by the current in the conductor to operate a motor which will propel the carriage and operate the painting mechanism or compressors. This is probably the preferred method of coating a power conductor and, if desired, an operator may attend the carriage so operated.

In the form. of apparatus shown in Fig.

1, the conductor 10 is used to transmit an alternating current. In order to take power from this alternating current, a magnetic core 11 with a secondary winding 12 is placed around the conductor. 1 This magnetic core may have a closed magneticcircuit or if made amply large may have an air gap. In general, the magnetic circuit will have a removable block or gap piece 13 shown in Fig. 2; the removable gap piece being used to allow the core to be slipped over the conductor and also to control the flux flowing in the magnetic corell which, in turn, will control the current or voltage in the secondary 12. It is evident that by adjusting the air gap the amount of flux flowing in the core may be adjusted'for Variations of current in the conductor 10. It 'is not necessary,'however, that this adjustment be made providing the apparatus to be operated will work over the range of current induced in the-secondary orwhere this is controlled by an impedance in the secondary circuit or by taps on the same. y

The current from the secondary circuitis run to'a motor l l which in turn is used to operate tractor wheels 15 to propel the carriage and also to operate coating rollers or brushes 16 which dip into a suitable coating tank 17.

It is readily seen that if the line is not in normal operation it may be short-circuited or grounded atany desirable place and sufiicicnt current sent throughit to operate the coatingmechanism. Under this condltlon,

the voltage ontlle line -maybe verysmall,

particularly if the point of short-circuit is in the vicinity of the place where the Work is being carried on. 'By short-circuiting the conductors in advance of the place where coating is being carried on, it; is:possible to have a high voltage on the line at the source of power in order to force the necessary current across the line, but-atthe same time the voltage will henegli'gible in the vicinity of the coating operations. V

A short may be placed between conductors in advance of the operation-or from a con ductor to ground which will reducethe po- .tential at this point. It, of course, is possible ..i:'or the operating motor to operatean airv compressor, if theconductor iscoated by ,means of ordinary spray guns or by appfa ratus specially designed for the work. Excess material maybe readilyremoved from the conductor by brushes or an air blast operated by the motor. It is evident that with this type of mechanism it'is possible to coat conductors in very inaccessible places and to supply the necessary power.-

In the stringing of conductors on their supports, the surface of the conductor is frequently damaged by drawing it over rocks or the tower members. Withthe above described equipment, it is very easy to smooth 7 upthe conductors by substituting the proper:

smoothing or polishing equipment for the coating brushes or rollers. It is also possible to remove dirt and smallpiecesof metal from the conductor. Manysmall pieces of metal areproduced during the drawing operation" which adhere to the conductor surface and promote discharge from the surface; hence, the removal of these will improve the condition of the conductor which might otherwise require a considerable length of time before the adhering particles would be removed by the action of the weather and other causes.

As a uniform roughness on the surface of a conductor tends to eliminate discharge points and, at the same time, provides a much better surface for the holding of the enamel or insulating covering, it may be advisable in some cases not only to clean the conductor so that the enamel will hold but also to further prepare the surface by means of a small scratch brush or sandblast. This can be readily taken care of by a carriage in advance of the one applying coating or can be driven by the same equipment providing there is enough energy. Unless a conductor has been weathered for some time, it is generally advisable to clean the surface in advance of applying the coating as oil or tallow used in the drawing of the conductor may interfere with the adherence of the coating. Much of the oil or grease and small chips which will tend to cause a discharge may be washed off by a suitable brush equipment which is substituted for the coating rollers; a washing fluid being substituted for the coating material. In general, however, it is advisable to do the washing far enough in advance of the coating so that it will not interfere with the proper application of the coating. In some conductors, however, the capillary attraction may be used to hold the wash water on the interior of the conductor. This will tend to prevent the insulating compound from being fed into the center of the conductor.

I claim:

1. The process of treating a conductor while in operative position in a transmission line comprising the steps of supporting treating apparatus on the conductor propelling the apparatus along the conductor by power derived from the current in the conductor, and operating said device independently of its movement along the conductor by power also derived from current flowing in the conductor.

2. The process of treating a conductor hav ing an alternating current flowing therein comprising the steps of moving a current transformer along the conductor while in position to be energized thereby and utilizing the current from the secondary of said transformer for operating apparatus independently of its movement along the conductor to treat the conductor.

3. Apparatus for treating a conductor while suspended in a transmission line comprising a carriage adapted to be supported on a conductor and to travel along said conductor, and a current transformer mounted on said carriage and having a removable core section to permit insertion and removal of the conductor to and from said core section.

4. Apparatus for treating a conductor while suspended in a transmission line comprising a carriage adapted to be supported on the conductor and totravel on said conductor, a current transformer having a core mounted on said carriage in position to be energized by current flowing in said conductor, said current transformer having a secondary winding, a motor mounted onsaid carriage, and treating. apparatus for said conductor operated by said motor.

'5. Apparatus for coating a transmission line conductor while suspended in position in the line comprising a carriage arranged to be supported on the conductor and to traverse the conductor, a current transformer core mounted on said carriage and having a removable section to permit insertion of the conductor in said core, said current transformer having a secondary winding, and a motor mounted 011 said carriage and energized by current from the secondary winding of said transformer, a traction wheel propelled by said motor for moving the carriage along the line, and treating apparatus mount- I ed on said carriage and operated by said motor.

6. Apparatus for coating a conductor while in position in a transmission line comprising'a pair of wheels adapted to travel on the conductor, a frame suspended from said wheels below said conductor, a transformer core mounted on said frame and having an opening therethrough for receiving said conductor, a portion of said core being movable to permit insertion of the conductor therein, a secondary winding on said transformer core, a motor mounted on said frame below said conductor and connected with said secondary winding to be driven by current induced in said secondary winding by current in said conductor, a driving connection between said motor and one of said wheels for propelling said frame along said conductor, and apparatus mounted on said frame for applying a coating to the outer surface of said conductor, said apparatus being driven bysaid motor.

In testimony whereof I have signed my name to this specification this 29th day of Aug. A. D. 1930.

ARTHUR 0.. AUSTIN. 

